Control units used in electronic ignition control are described in Bosch Technical Information, Combined Ignition and Gas Injection System MOTRONIC (1 987 722 011, KH/VDT-9/85-De). From information pertaining to load and speed, temperature and throttle valve position, the control unit determines controlled variables, such as ignition advance angle and dwell angle, between two ignition processes. In this connection, the controlled variables are defined on the basis of stored (engine characteristics) maps. The map for defining the ignition advance angle is determined by engine bench testing, and is optimized in the vehicle in conformance with specifiable criteria, such as fuel consumption, exhaust, and performance, and is subsequently stored. This facilitates a ready adaptation to every operating state, as well as good vehicle performance, fuel economy, and exhaust gas ratings.
The control unit known from the related art contains a microcomputer, which defines the controlled variables from the operating parameters by extracting the ignition-advance angle from the map. Furthermore, the ignition-advance map angle is able to be adapted to various operating conditions. Thus, the ignition is able to be adjusted to favorable exhaust values, proper dynamic wheel balance, and good fuel economy in idle operation, for example, while vehicle performance and fuel consumption are in the fore in part throttle operation.
In the case of initial load (preload), the emphasis is on achieving maximum torque, while avoiding knocking. The ability to change the ignition-advance angle in conformance with the logic gating of various signals makes it possible for the ignition-advance angle to be individually adapted to every operating state of the engine. Thus, considerable consideration is given to the specific engine requirements, e.g., in the special operating states, start-up, idle operation, overrun (deceleration), and initial load. The ignition-advance angle in question is thus able to be shifted by any desired value as a function of various switch point signals.